While a great, feel good, notion, this does not allow him to "grow substantially this season". People on here like to hammer the notion of "don't give away your work", but if that promotion is legitimately looked at as the cost to acquire a customer, as any other marketing is, there is no problem with it. If there is any issue with "giving away" a Spring Cleanup, it should be that you should never front-load a promo and that a cleanup is, in this situation, likely a high cost to acquire a customer. If you view it only through the lens of "giving away work", you're missing the bigger, long-term picture.

The ROI on advertising is important.

Though to give away that much free work that in effect has you low balling is never an acceptable give away. It takes time to build up pricing. No time to tear what was built up.